Research is being conducted on the biological mechanisms that control chemotaxis and proliferation of various cell types in diabetic retinopathy, which include fibroblasts, glia, pigment epithelium, and vascular smooth muscle. Using wound repair as a general model, we have demonstrated that glial cells exhibit chemotaxis to platelet-derived growth factor (PDGF) in a fashion similar to that described in previous reports on smooth muscle and fibroblasts. In addition, we are characterizing and purifying a potent chemoattractant present in retina which attracts both fibroblasts and glial cells present in bovine retina.